Surfacing of inking rolls



Dec. s, 1936. B. w. HUBBARD 2,063,037

SURFACING OF INKING ROLLS Filed Aug. 29, 1932 Patented Dec. 8, 1936 UNITED STATES PATENT `QFFICE SURFACING OF INKING ROLLS Application August 29,

Claims.

This invention relates to the coating of cylindrical inking rolls for printing presses to form a film of printing composition on the surfaces thereof.

'Ihe general aim of the inventionv is to provide a new and improved method of applying the composition to a roller surface which insures the formation of a coating of approximately uniform thickness over all parts of the surface, which may be carried out with simple and inexpensive apparatus by unskilled workmen and with a minimum amount of composition maintained in molten state.

In carrying out this object, the invention contemplates the maintenance of molten composition in a layer of substantially uniform thickness through which the roller to be coated is passed in an endwise direction and at a substantially uniform rate so that equal amounts of composition will be applied to different unit areas of the surface and such areas will be heated to the same degree by the molten composition.

Another object is to provide a novel apparatus in which the above process may be carried out.

The invention also resides in the novel manner of applying molten composition so as to prevent the occurrence of air bubbles in the film of composition on the roller surface.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawing, in which Figure 1 is an elevational View of apparatus for coating inking rolls in accordance with the l present invention.

Fig. 2 is an enlarged fragmentary sectional view of a portion of the apparatus shown in Fig. 1.

Fig. 3 is a fragmentary elevational view of a part of the coating apparatus.

Fig. 4 is a fragmentary perspective View of a part of the coating apparatus.

With the apparatus shown in the drawing, each roller 5 tobe surfaced is disposed in vertical 45 position during coating and the molten composition is applied throughout the length of the roller by eecting relative vertical movement between the roller and a receptacle 6 adapted to contain a layer of composition surrounding the periphery of the roller. Preferably, such movement is obtained by raising the roller which may be suspended from a cable I coupled to one end trunnion 8 of the roller and extending around a pulley 9 and thence around a winding drum I0 driven through appropriate speed-change mech- 1932, Serial No. 630,844

anism by a reversible and constant speed driving means such as an electric motor H. The hoisting mechanism thus employed may be supported by a vertical post I2 pivoted to swing laterally between the coating position shown in full lines in Fig. 1 and an unloading position shown in dotted outline.

The receptacle Imay be relatively shallow and preferably has a bottom wall I3 converging toward a central opening through which the roller extends during coating. Around said opening isv a ring I4 of flexible material such as rubber and of such size as to bear'against the periphery of thev roller and provide an effective seal therearound while at the same time permitting the roller to be drawn upwardly through the composition in the receptacle.

Thelcomposition to be used in coating is melted and maintained at a substantially uniform temperature in a water-jacketed tank I5 which Y.

preferably is relatively small and deep so that the volume of composition required to be kept in storage is reduced to a minimum. Molten composition from the tank is delivered at a uniform rate of flow to the receptacle B which, in the form shown in Fig. 1, is accomplished by a constant discharge pump I5 driven by an electric motor I1. For this purpose, the pump inlet communicates with an outlet I8 at the bottom of the tank and the outlet communicates through a pipe I9 30 with the receptacle 6 at a point below the normal level of the liquid therein. The rate of flow of composition to the receptacle may be varied by manipulating a valve 20 thereby causing more or less of the composition delivered by the pump to be by-passed back into the tank through a pipe 2I.

Since the composition is delivered to the pump under pressure and discharged into the receptacle below the level of liquid therein, the possibility of air bubbles becoming entrapped in the composition in the receptacle or in the film retained on the roller surface is entirely eliminated. Air bubbles may also be eliminated with the gravity feed system shown in Fig. 3 wherein the tank I5 is placed above the receptacle 6 and the flow of composition to the latter regulated by a valve 22.

Owing to the inherent physical nature of ther composition employed, the formation of a film of uniform thickness throughout the length of the roller is dependent to a large extent upon the uniformity with which the successive longitudinal sections of the roller are heated in passing upwardly through the layer of composition in the 55 receptacle a quantity of molten composition in. excess of that required for coating the roller and such excess overflows through the pipe 23 and is returned to the tank I5.

To catch the composition discharged downwardly through the receptacle opening when the lower end of the roller passes out of engagement with the ring I4, a basin`25 is swingably mounted on the tank frame and thus adapted to be moved in beneath the receptacle after the roller has-been yraised nearly through the receptacle. The composition falling into the basin drains back into the tank I5.

In operation of the apparatus above described, the roller to be coated is first coupled to the cable 1 and, by rotationof the drum II) in the proper direction under the control of a motor switch 2B, is lowered through the receptacle 6 into a pity 21. The direction of the motor drive is then reversed and the roller raised until the upper end engages the underside of the ring I4 and raises the same slightly as shown in Fig. 2 whereupon the motor is stopped. The pump I6 is then started and the flow of composition into the receptacle adjusted until an excess of ccmposition continues to overflow into the pipe 23. Next, the motor is started in a direction to raise the roller. As the roller is thus drawn upwardly through the layer of molten composition, the successive longitudinal sections thereof `are exposed to the composition for equal intervals of time and a lm thereof adheres to the roller surface` The heat imparted to the roller by the composition is returned to the composition on the surface prolonging the downward draining along that portion of the roller surface disposed above the level in the receptacle. But, owing tothe uniformity of heating produced as above described, such draining takes place approximately uniformly throughout the length of the roller leaving a film of uniform thickness as the composition congeals in cooling.

As the lower vend of the roller approaches the ring I4, the basin 25 is swung in beneath the' roller so as to catch the composition discharged from the receptacle as the lower end *of the roller passes out of contact with the ring. The entire surface of the roller will then be coated and the roller may be swung to one side and stood yon end to permit draining of the composition substantially constant rate of ow sufcient to maintain an overflow from said outlet, and power driven means for raising said roller at a uniform speed whereby to present successive longitudinal sections of the roller to the layer of composition in said receptacle.

2. In a machine of the character described, an upwardly opening receptacle having a bottom opening adapted to be closed by a roller to be coated when the latter extends in a vertical direc- ,tion through the opening, means to supply molten composition to said receptacle at a rate in excess of the amount required for coating a roller, an overflow outlet for withdrawing molten composition from. the top of the body of composition in said receptacle whereby to maintain a substantially constant liquid level therein, and means for eii'ecting relative vertical movement between said roller and said receptacle at a substantially uniform speed and in a direction to expose successive longitudinal sections of the roller to said composition beginning at the upper end of the roller.

3. In a machine of the character described, a tank for containing a supply of molten composition and having an outlet near the bottom thereof, areceptacle having a bottom opening adapted to receive a roller with its axis in vertical position, an overow outlet within said receptacle, means operable to withdraw composition from said tank below the level of liquid therein and deliver the same to said receptacle below the level of said outlet and at a rate of flow such as to means for raising said roller through the receptacle at a substantially uniform speed.

4. Apparatus for coating a roller with printers composition comp-rising means to support the roller with its axis in upright position, a receptacle adapted to contain a bodyV of molten composition contacting the surface of said roller around the entire periphery thereof, means for effecting relative movement between said body of composition and said roller in a direction endwise of the latter, a tank for storing molten com.- position, means operating to withdraw composition from said tank below the level therein and deliver the composition to said receptacle below the level of the composition in the latter, an

overflow outlet for said receptacle operable duringcoating of the roller to remove aircells accumu-l lating at the surface of `the composition ln lthe receptacle, and means for returning the' overflow to said tank.

l 5. Apparatus for coating a yroller with printers composition comprisingmeans to support the roller with its axis in upright position, a receptacle adapted to contain a body of molten composition contacting the surface of the roller around the entire periphery thereof, means for effecting relative movement between said vbody ofv composition and said roller in adirection end-,

wise of the latter, means operable during 'at least a part of said relative movement to deliver molten composition to said receptacle at a pointbelow the level Vof the composition therein, and an overmulating air cells from the coating retained on the lroller surface.

BRUCE W, HUBBARD. v 

